Conventionally, an electronic device having an electronic element that is surface-mounted on a substrate as a semiconductor package or the like may have a heat sink on an opposite side of the substrate relative to the electronic element. The heat sink may serve as a separation of an electric connection path that connects the electronic element and the substrate from a heat dissipation path for transferring heat to the heat sink from a conductor part on a back-side of the electronic element. A space between the back-side conductor part and the heat sink is filled with a heat conductive material, such as, a gel-like insulation heat dissipater according to a disclosure of a patent document 1 (i.e., Japanese Patent Publication No. JP-A-2002-50722).
A well-known structure for interposing a certain gap between a substrate and a heat sink is, for example, realized as a configuration in which a heat sink is provided with a support part disposed thereon in a protruding shape, on which the substrate is placed and fixed with a screw to the heat sink.
In such a configuration, a distance or insulation gap between the back-side conductor part of the electronic element and the heat sink decreases when the substrate warps toward a heat sink side due to a temperature change, a pitch/interval between two support parts, thickness of the substrate or other causes. The decreased distance, or the decreased amount of the insulation gap, may be smaller than a threshold distance, i.e., a guaranteed insulation distance, of the insulation heat dissipater, thereby leading to a breakage of the electronic element by a zero insulation gap, i.e., a conductive contact or a short circuit between the back-side conductor part and the heat sink.
As a counter-measure for the above, a height management of the electronic element, a solder height management, a warpage management of a substrate, or the like may be performed in a manufacturing process, which may lead to an increased management costs. Alternatively, to assure a sufficient insulation gap during a substrate warped state, a greater distance between the electronic element and the heat sink may be provided together with a greater amount of thickness of the insulation heat dissipater, which in turn deteriorates the heat dissipation characteristics of the electronic element.